Magnum primers in non-magnum loads

[samari46]

I've used CCI mag primers for my hunting ammo in my Sako 75. Prior to that I've used them in at least 5 model 70 rifles. 4 target rifles and one standard rifle. This is with IMR 4350. And have been doing do for over 30 years. Lower Sd's in the low teens. I use 54.5-55.5 grs IMR 4350 165 grain Nosler Ballistic tip. Chronos out to just a hair over 2800 fps. That load was worked up with the mag primers. Frank

[DeltaPapa]

Informal testing of SPP vs SRP vs SMP in 9mm; https://www.okshooters.com/threads/s...esults.304327/
Author gave me permission to cross post here.

[fourclicks]

Same position as others trying to save my LR primers for competitive shoots. But I used LR mag primers in my springfield and found no difference with previous loadings 190 gr bullet with 19.5 grs. of Win. 1680 pwder. very please with the out come

[badguybuster]

I will use mags in 9mm quite often. I drop my normal load by 10% when i do and it seems to work pretty well.

[Motor]

Rule of thumb when going from a standard primer to a magnum primer in a rifle load such as .308 Win for example is to back off 1 or 2 grains and work back up if needed. From my own personal experience I typically end up with the same powder charge weight but its better to be safe.

Motor

[flounderman]

probably get better accuracy from standard primers. I have used magnum in almost all rifle calibers for years, but usually with ball powder.

[stubshaft]

I was getting erratic results in my .338 WM using large rifle magnum primers. I had some cases primed with regular large rifle primers and decided to load some Lyman 33889 boolits in them ahead of 16.5 grs Unique. This really tightened up the groups!Attachment 276915

[jetinteriorguy]

I did a small test to see the difference in a load using LRM primers in 45ACP.
My standard load is a mild load of 700X in the 45ACP with a 200 gr SWC bullet.
I have no way of testing pressure but the mag primer loads were 50fps faster than the standard LP primers.
Other than that I saw no difference.

LRP and LPP primers are not the same size and should not be substituted one for the other. SRP and SPP however are the same size and can be subbed as long as you drop the charge down and work up checking for pressure and reliability.